The invention is related to the field of space vehicles for use in launching a payload from a stationary ground-based position into orbit, and specifically to an adapter for connecting at least a first and second rocket stage of a space vehicle.
Rocket powered space vehicles used in space missions can generally be categorized into launch vehicles and payloads. Launch vehicles provide the primary thrust for launching and delivering a payload from the earth""s surface into orbit. Launch vehicles generally include two or more rocket stages arranged to fire at different times as the launch vehicle travels from the earth""s surface into orbit. The rocket stages are fired sequentially and typically include at least a first stage or booster stage rocket and a second stage or upper stage rocket. The booster stage rocket is designed to launch and deliver the payload a pre-determined distance above the earth before exhaustion. Upon exhaustion, the booster stage rocket is jettisoned and the upper stage rocket is fired to deliver the payload the remainder of the distance into a desired orbit. Once in orbit, a payload such as a satellite, interplanetary probe, or the like is released from the upper stage. In some cases, the payload may include propulsion subsystems for orbital maintenance, attitude control, and orbital transfer depending on its intended function.
The jettisoned booster and upper stage rockets typically fall back toward the earth where they either bum up in the earth""s atmosphere or reach the ground or a body of water. The separation of the rockets is accomplished using adapters that connect the various rocket stages and ultimately the final rocket stage to the payload. The adapters are designed to separate at a forward interface from the next sequential rocket stage, while a rear interface of the adapter remains attached to the separated rocket stage and returns to earth or is destroyed with the separated rocket stage in the earth""s atmosphere. Several techniques are utilized to separate the adapter and exhausted rocket stage from an upper rocket stage or payload. Some common techniques include pneumatic, hydraulic, and pyrotechnic joints.
Because of the expensive nature of disposable rockets, an emphasis exists on the development of reusable launch vehicles. Reusable launch vehicles utilize rocket stages that include methods and apparatus for a controlled return to the earth""s surface that prevents damage upon impact or entry and travel through the earth""s atmosphere. The rocket stage may then be recovered and used in future space missions with little or no refurbishment.
The present invention generally relates to an adapter for connecting rocket stages of a space vehicle. In the context of the present invention, a rocket stage is defined as one or more rocket sections, e.g. separate rockets with individual thrust sources, or a rocket section and a payload. The present adapter provides specific advantages when used with reusable rocket stages, but those skilled in the art will appreciate that the adapter described herein could easily be used to connect any two rocket stages or a rocket stage and a payload.
In view of the foregoing, a primary object of the present invention is to provide an adapter for joining rocket stages. Another object of the present invention is to provide an adapter that upon separation of the rocket stages, the adapter itself is at least partially separatable from an exhausted rocket stage. Another object of the present invention is to protect the exhausted rocket stage during a return flight back to the earth""s surface. Another object of the present invention is to enhance the aerodynamic characteristics of the exhausted rocket stage to facilitate the return flight back to the earth""s surface.
One or more of the above-noted objectives, as well as additional advantages, are provided by a first aspect of the present invention, which includes an adapter for connecting a first rocket stage and a second rocket stage. The adapter forms a first interconnection between the second rocket stage and the adapter that is separatable by a first separating system. The adapter also forms a second interconnection between the first rocket stage and the adapter that is separatable by a second separating system. That is, the adapter not only separates the first and second rocket stages, but also subsequently separates from the first or exhausted rocket stage. Where the first rocket stage is a reusable rocket stage, separation of the adapter from the first rocket stage xe2x80x9ccleans upxe2x80x9d the first rocket stage for a controlled descent and flight back to the earth""s surface.
Various refinements exist of the features noted in relation to the subject first aspect of the present invention. Further features may also be incorporated in the subject first aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. For instance, the adapter of the subject first aspect may define an elongated housing made up of a plurality of detachably interconnected adapter sections (e.g., first, second, and third adapter sections). The adapter sections may be interconnected by any suitable method (both in terms of how the structural interconnection between the individual adapter sections is established and how the individual adapter sections are separated from each other). In the case where three such adapter sections are used, the interconnected adapter sections define a first, second, and third separation interface at the interconnections of the mating edges of the adapter sections. In one embodiment, the interconnected adapter sections could connect at a base thereof to the first rocket stage and include a ribbed interface about their exterior surface that mates with the second rocket stage to connect the first and second rocket stages.
Any appropriate way of detachably interconnecting the adapter with each of the first and second rocket stages may be used (both in terms of how the structural interconnection is established, and how the adapter is separated from both the first rocket stage and the second rocket stage). For instance, the separating systems could include numerous apparatus, e.g. pyrotechnics, hydraulics, and mechanical devices. In one embodiment, the first or second separating system may include an explosive fastener assembly, such as low shock producing explosive bolts, that are used to connect the base of the elongated housing to the first rocket stage. In another embodiment, where the adapter includes the plurality of adapter sections, an adapter section separating system may be utilized that includes at least one pulley mounted on one of the adapter sections, e.g. the first section, and at least one other pulley mounted on a mating adapter section, e.g. the second section. A cable alternatively wound between the pulleys and connected at one end to the first section and the other end to the second section may secure the two sections together. A similar set of pulleys and cable may then be used to secure the other adapter sections together to form the housing for the adapter, e.g. the second and third sections and the third and first sections. One or more cutting devices may also be included in the adapter section separating system to cut the cables at the desired separation time to release the first, second, and third adapter sections thereby separating the adapter sections.
The adapter of the subject first aspect may be used in combination with a shield apparatus that remains connected to the first rocket stage. In this characterization, the shield apparatus may be internally contained within the above-noted elongated housing. The adapter and shield apparatus may be characterized as a rocket stage interconnect assembly. In this characterization, the shield apparatus is longitudinally deployable relative to the first rocket stage, following the separation of the adapter from the first rocket stage (which is after the separation of the adapter from the second rocket stage). The longitudinal deployment of the shield apparatus may be used to protect surfaces, e.g. the interface between the base of the housing and the first rocket stage, that are exposed by the separation of the adapter from the first rocket stage. Preferably, the shield apparatus is aerodynamically designed to facilitate flight of the first rocket stage back to the earth""s surface (e.g., in the form of a cone).
A second aspect of the present invention is a space vehicle that utilizes the above-described adapter to connect a first rocket stage and a second rocket stage. The first and second rocket stages may be a first and second rocket stage or a rocket stage and a payload. In this regard, at least one of the first and second rocket stages includes a propulsion source, such as a rocket engine.
Various refinements exist of the features noted in relation to the subject second aspect of the present invention. Further features may also be incorporated in the subject second aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. For instance, the first and second rocket stages may be reusable rocket stages that include an aerodynamic control system and control surfaces for guidance back to the earth""s surface following separation and/or delivery of a payload into a desired orbit. In this characterization, the above-described adapter could be used to separate the rocket stage from the payload followed by a separation of the adapter, e.g. the first, second, and third adapter sections. Preferably, in the subject second aspect, the adapter is used in combination with the above-noted aerodynamic shield apparatus for facilitating the controlled descent of the rocket stage and protection of the rocket stage during flight back to the earth""s surface.
A third aspect of the present invention is a method for separating a first and second rocket stage. The method includes at least the step of separating the first rocket stage and an adapter connecting the first and second rocket stages from the second rocket stage. Additionally, the method includes the steps of separating the adapter from the first rocket stage and longitudinally deploying an aerodynamic shield or cone relative to the first rocket stage.
Various refinements exist of the features noted in relation to the subject third aspect of the present invention. Further features may also be incorporated in the subject third aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. For instance, the step of separating the adapter from the first rocket stage could include the step of separating at least two of the above described adapter sections from the first rocket stage. Prior to the step of separating the at least two adapter sections, the at least two adapter sections are interconnected together and to the first rocket stage to form a housing about the aerodynamic shield or cone. Thus, the step of separating the at least two adapter sections could include the steps of separating a base of the interconnected adapter sections from the first rocket stage followed by the separation of the adapter sections themselves.
According to the present method of the third aspect, the step of separating the base could include the step of actuating the above-described low shock producing explosive bolts to release the fastener assembly connecting the base of the interconnected adapter sections to the first rocket stage. Furthermore, the step of separating the individual adapter sections could include cutting at least one or more cables securing the adapter sections together.
According to the method of the third aspect, the step of longitudinally deploying the second portion of the adapter could include retracting the aerodynamic shield or cone relative to the first rocket stage to form a seal between the aerodynamic shield or cone and the first rocket stage. The seal could be a pressure seal and/or a thermal seal that protects internal components of the rocket stage during the flight back to the earth""s surface.
A fourth aspect of the present invention is embodied in a method for separating a first rocket stage from a second rocket stage, each of which has a propulsion source/system. During flight, the second rocket stage separates from an adapter that previously interconnected the second rocket stage with the first rocket stage. The propulsion source/system of the second rocket stage may then be used to continue the flight of the second rocket stage. Some time after this initial separation and before the first rocket stage returns to earth, the adapter may be separated from the first rocket stage.
Various refinements exist of the features noted in relation to the subject fourth aspect of the present invention. Further features may also be incorporated in the subject fourth aspect of the present invention as well. These refinements and additional features may exist individually or in any combination. It will also be appreciated that any and all of the features discussed above in relation to the various aspects may be used alone or in any combination.